1. Field of the Invention
The invention relates generally to cementing equipment used with oilfield wellhead equipment and, in particular aspects, to couplings that are useful for such equipment.
2. Description of the Related Art
After a hydrocarbon wellbore has been drilled, a casing is typically cemented in along the length of the drilled bore. Cementing equipment is used to do this and typically includes a top drive cement head that permits balls or rubber darts to be dropped into the wellbore during the cementing operation. The cement head also must be capable of flowing cement from a cement supply downwardly into the wellbore. Suitable cementing equipment for these purposes includes a top drive cement head which is available commercially from Baker Hughes Incorporated of Houston, Tex.